Recently, there have been more occasions in which video images received by a television, video images reproduced from media such as a Blu-ray Disc, and personal computer (PC) screens, for example, are projected on a large-sized screen using a projection-type image display device so that a plurality of persons view them or make presentations. In addition, there also exists a small-sized projection-type image display device (pico-projector) that is used on a palm or mounted on a mobile device.
In addition, there is also developed a projection-type image display device including a laser or a light emitting diode (LED) as a light source and having high color saturation and satisfactory color reproducibility. By deflecting irradiation light from the light source with the use of, for example, a micro electro mechanical systems (MEMS) mirror to perform dimensional scanning on a screen, it is possible to display an image by a residual effect thereof.
For example, there is proposed an image projection device that includes a dimensional scanning unit formed by combining a mirror that performs scanning in a horizontal direction with a mirror that performs scanning in a vertical direction and synchronizes horizontal scanning and vertical scanning of light beams to form a projection image on a screen (see, for example, Patent Literature 1).
In a case where an image is projected, it is problematic in that the image is deflected to have a trapezoid shape because the image is obliquely projected on a projection object (screen wall surface or the like). For example, there are proposed a method of correcting trapezoid distortion by controlling an amplitude of an oscillating mirror depending on a position of a vertical axis (see, for example, Patent Literature 2) and a method of correcting trapezoid, without reducing an effective pixel, by controlling a timing at which an oscillating mirror is irradiated with laser beams to make fine adjustments to a pixel position (see, for example, Patent Literature 3). There is also proposed a method of correcting distortion generated at the time of oblique projection by, in a case where an irradiation center direction of laser beams and an irradiation surface have a projection angle which is not right angle, storing, in advance, coefficient information on a polynomial expression for obtaining an irradiation position of laser beams on the basis of an angle of a reflective optical element, applying a coefficient obtained by calculating the coefficient information and the angle of the reflective optical element to the polynomial expression to calculate an irradiation position of laser beams, reading pixel information corresponding to the irradiation position from a frame memory, and oscillating a laser oscillator at brightness corresponding to the pixel information (see, for example, Patent Literature 4).
However, in a projection-type image display device including a light source such as a laser and a deflection mirror device that performs dimensional scanning on a screen with laser beams, there are shape distortion caused by not vertically irradiating a MEMS mirror with laser beams and brightness distortion caused by sparsity and density of output points of lasers and an irradiation angle onto the screen.